Flexible coupling for rotatable shafts

Abstract

A flexible coupling for rotatable shafts in the form of a metal bellows features a concentric sleeve which is fastened to one end of the coupling and which terminates in a plurality of fingers or keys projecting into, but without contact with, slots in the opposite end of the coupling. In normal use, the coupling transmits rotary motion from one shaft to the other shaft solely through the connecting bellows which provides the flexibility required for small amounts of misalignment and obliqueness of the coupled shafts. If the bellows broke, the concentric sleeve would function as the fail-safe coupling member to continue the transmission of the rotary motion.

What is claimed is: 
     
       1. A flexible coupling for rotatable shafts which comprises a metal bellows as the primary connecting element between the two ends of said coupling, said bellows having corrugations disposed only adjacent said two ends of said coupling, and a concentric sleeve attached to one of said ends and extending toward the other of said ends, said other end having a plurality of slots and the free end of said sleeve having a plurality of keys projecting into said slots without making contact therewith so long as said bellows is not ruptured, and said sleeve being disposed out of contact with said bellows. 
     
     
       2. The flexible coupling of claim 1 wherein the corrugations of the metal bellows are made of contoured diaphragms welded together. 
     
     
       3. The flexible coupling of claim 2 wherein the metal bellows is made of stainless steel. 
     
     
       4. The flexible coupling of claim 1 wherein the concentric sleeve has three keys equally spaced from one another. 
     
     
       5. The flexible coupling of claim 4 wherein the metal bellows is made of stainless steel. 
     
     
       6. The flexible coupling of claim 1 wherein the concentric sleeve is disposed within the metal bellows. 
     
     
       7. The flexible coupling of claim 1 wherein the keys have means to prevent the disengagement of said keys from the slots. 
     
     
       8. The flexible coupling of claim 1 wherein the metal bellows is disposed within the concentric sleeve having three keys equally spaced from one another and the corrugations of said bellows are made of contoured diaphragms welded together.